1. Technical Field
This invention relates generally to the electromechanical speech aids commonly referred to as artificial larynxes and as electrolarynxes, and more particularly to an improved electrolarynx construction with increased functionality.
2. Description of Related Art
A person without normal use of their vocal cords or larynx often uses an electrolarynx to speak. The electrolarynx includes a sound-producing component that delivers an electrolarynx tone (e.g., a buzzing sound) having a fundamental frequency in the speech range of the average human voice. To speak, the user introduces this artificially generated tone into a resonant speech cavity (i.e., the mouth, nose, or pharynx). While doing so, the user modulates the electrolarynx tone by varying the shape of the resonant speech cavity and by making the usual tongue, teeth, and lip constrictions so as to articulate the modulated tone as human speech.
U.S. Pat. Nos. 5,812,681; 6,252,966; 9,031,249; and U.S. Pat. No. 9,116,539 issued to Clifford J. Griffin describe some existing electrolarynxes. Each of those electrolarynxes typically includes a four-inch to five-inch long case that houses an electronic circuit board, a battery, an electro-mechanical transducer for producing vibrations (i.e., the electrolarynx tone), a volume control, and a power switch. The user grasps the case in one hand, actuates the power switch and volume control, and then presses the transducer portion of the electrolarynx against the outside of their throat so that electrolarynx tone vibrations travel through the throat tissues and into the mouth and throat for modulation and articulation.
One such electrolarynx includes a pressure-sensitive resistor (PSR) coupled to a pushbutton; the user depresses the pushbutton with their thumb to actuate the power switch while varying the pressure on the PSR. The PSR is connected to electronic circuitry that varies the frequency of the electrolarynx tone according to changes in the amount of pressure applied to the PSR. That way, the pushbutton-PSR combination enables both electrolarynx power-on and frequency variation of the electrolarynx tone with minimal, unnoticeable movement of the user pressing the pushbutton. Operation is easy, and a wide and continuous range of frequencies allows for increased control and subtle voice inflection, including syllable-specific intonation which may be used to approximate regionally specific or country specific voice patterns. Nevertheless, variation of electrolarynx volume is not as easy.